1. Field of Invention
The present invention relates to a backlight module, and more particularly, to a mold frame of the backlight module.
2. Description of Related Art
Since liquid crystal display (LCD) devices are non-emissive type display devices, they require external light sources to display the images. Generally, a backlight module is disposed behind a LCD panel to provide light to the LCD panel. The backlight module is an important component that greatly influences the display quality of the LCD device.
FIG. 1A is a schematic, exploded view of a conventional backlight module. FIG. 1B is a schematic, top view of the conventional backlight module in FIG. 1A. FIG. 1C is a cross-sectional view from the A-A line in FIG. 1B. Referring to FIG. 1A, FIG. 1B and FIG. 1C, the backlight module 100 includes a back cover 105, a light guide plate 110, a light source 112, at least one optical film 115 and a mold frame 120. The mold frame 120 includes a front frame 124 and a lateral side 122 of the front frame 124.
A liquid crystal display module can be fabricated by assembling the backlight module with a liquid crystal cell (not shown). However, the conventional backlight module may become defective when the ambient temperature varies. This is because the mold frame 120 constrains the components of the backlight module 100 that have different thermal expansion coefficients. More specifically, the front frame 124 presses the edges of the optical film 115. A display problem of the liquid crystal display module thus arises when the ambient temperature varies, because the optical film 115 becomes warped and presses the polarizer of the liquid crystal display module.
Accordingly, providing a backlight module that can prevent the liquid crystal display module from being defective when the temperature varies is an issue of great consequence.